Radiator manufacture



July 2. KARMAZIN 2,206,286

RADIATOR MANUFACTURE Original Filed Jan. 25.` 1955 2 Sheets-Sheet 2 897%.' INVENTOK WMTJ/R-f July 2 1940- J. KARMAzlN RADIATOR MNUFCTURE 2 Sheets-Sheet 1 Original Filed Jan. 25, 1935 INVEANTOR.

Patented. July 2, 1940.

PATENT ol-*FiclaA RADIATOR MANUFACTURE John Karmazin, Grosse Ile, Mich., assignor, by mesne assignments, of one-half to Rose M. Karmazn, Grosse Ile, Mich.

Original application January 25, 1935, Serial No.' l

Divided and this application November 20, 1937, Serial No. 175,665

2 Claims. (Cl. 257-139) Heat exchangers made of sheet metal, and through which liuids under pressure ilow, have generally been made of one main material from which the structure derives its strength, and hence I refer to this material as the structural material. The structural material has been held together by a second material which bonds together the structural material. I refer to this second material as the bonding material.

Prior to my invention, it was generally considered desirable to use a structural material having a relatively high coefficient of conductivity, as it was considered that the structural material would perform the major conducting function of the heat exchanger. In these prior heat exchangers theA bonding material generally was considered a detriment, since the bonding material was quite likely to have a much lower coeicient of conductivity than the structural material, and was quite likely to produce films of relatively low conductivity at the bonded joints. This was true with respect to heat exchangers in which copper, or copper alloy, was used as the structural material, and various lead containing i solders were used as the bonding material.

Prior to my invention, attempts had been made to make heat exchangers of such relatively low conducting material as sheet steel; but in those attempts, the major flow of heat had to take place through the relatively low conducting sheet steel. If any bonded joints were provided, they were of such a character that they were of no material aid in the conduction of heat from one side to the other side of the heat exchanger.

In my invention, I have provided a `heat exchanger having as its structural material sheet steel; but I have used a relatively high conducting bonding material, such as coppery orcopper alloy, in such a manner that the bonding material not only provides no resistance to the ilow of heat, but very materially. aids in the conduction of heat from one side of the heat exchanger to the other. The arrangement is such that a heat exchanger, made according to my invention, in which the structural material is sheet steel, has substantially the same heat exchange capacity as previous, similarly constructed, heat exchangers in which Vthe structural material had a relatively high coeilicient of expansion.` That is,` a heat exchanger made in accordance with my in vention and in which the maJor or structural portion is of sheet steel, has substantially the same heat exchange power as a similarly constructed heat exchanger in which the major 4portion or structural material is of copper or of a exchange and power at a much lower cost; and

notwithstanding this llower cost, the heat exchanger is very much stronger, structurally, and is equally as good a Vconductor of heat.

I accomplish the foregoing by working the sheet steel in such a manner that a series of sheet steel rings or loops are nested, between which there is provided a series of copper, or copper alloy, rings which bond the sheet steel rings, and at the same time provide unbroken paths of highly conducting material between the inside and outside of the heat exchanger thus produced. The heat flowing either inwardly or outwardly through the tube, is thus enabled to seek an unbroken path of very low resistance along the bonding material. The bonding material very materially aids in the conduction of heat, so that the combined conducting power of the sheet steel and of the` bonding material is substantially equal to that formerly obtained by the relatively expensive forms using copper or copper alloy as the structural material. This result is accomplished partly by the fact that the copper, or copperalloy, used in my construction, forms a relatively wide band of cuprous alloy with thesheet steel along the bonding ring and this provides a relatively Wide band of relatively god conducting material along the bonding ring. t

Itis, therefore, an object of my invention to provide a tubular heat exchange unit, made oi' sheet steel, and bonded together by copper, or copper alloy, in such a manner that the conducting power of the sheet steel is very materially aided by the large number of heat conducting paths of high conductivity extending unbrokenly from the interior to the exterior ofthe tube.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accom? panying drawings, wherein a preferred form oi' the present invention is clearly shown.

In the drawings:

Fig. 1 is a perspective of a heat exchanger embodying my invention; v,

Fig. 2 is a cross-section of the unit shown in Fig. 1, shcwing the unit in a horizontal position as it lies on its side before it is subjected to the bonding operation during its manufacture;

Fig. 3 is an enlarged cross-sectional view taken along the line 3-3 of Fig. 2; f

. Fig. 4 is a view, somewhat similar to Fig. 3,

vshowing the bonding material as it is being distributed between the joints of the structure dur. ing the process of manufacture;

Fig. 5 is la View, somewhat'similar to Fig. 4, showing the joints in their completed stage.

A heat exchange unit made in accordance with my invention may include a-plurality of ns I0 which have formed therein a plurality of integral projections, loops .orrings II by any suitable forming method. Preferably the ns I0 are made from a single strip of sheet steel in which the projections or rings II are formed at proper intervals. Thereafter the strip is cut in proper length to form the ns I0. The fins I0 are stacked with the loops or rings II in nested relation as shown in Fig. 2, the ns beingl pressed together slightly to form a fairly tightjont between the nested portions of the rings. Preferably the rings II are cone-shaped; but any form of projection may be made which is adapted to nest within the adjacent projection. If desired, suitable header constructions are placed at the ends of the longitudinal tubes I2. In the structure shown, these headers are formed at one end of the radiator by providing stampings I3 from which cones or rings I4y have been formed, and the edge of which has been anged around a cup I5 as indicated at I5a. At the other end of the radiator, theheaders are formed from the stamping I6 in which the cones or ring I1 are directedinwardly into the header instead of outwardly. The edge of the stamping I 6 is bent around the edge of the cup I8 as indicated at I9. In the construction shown in the drawings, the headers form a sinuous passage with the tubes I2; but it is to be understood that anyconnections may be used with the tubes I2, so that either individual fluids may be fed through the tubes I2 or a single fluid may be fed through the tubes in series and/or parallel relationship.

The rings II are bonded together as shown in Fig. 5, so that the'joints between the rings II provide bonding rings 20a of material having la relatively high coefficient of conductivity.4 The resulting structure forms a tube of nested rings alternately indicated bythe numerals II and 20a in Fig. 5, rings II being of steel, which is of relatively low conductivity, and rings 20a being of bonding material having a relatively high coefficient of conductivity, such as copper' or copper alloy. To accomplish this I manufacture my heat exchange unit by inserting strips; 20 (Fig. 3) of bonding material into the tubes I2 before the heat exchange unit is closed up by the headers, and, if desired, the strips 20 may be madeA long enough so that the ends thereof extend into the headers to provide bonding material for the headers. Instead, a slight amount of bonding material may be provided for the headers-separately from the strips 20. l

l After the heat exchange unit has been assembled', as heretofore described, the same is placed in a horizontal position and is subjected to heat,

as by being introduced into a brazing furnace.

in which a reducing atmosphere, such as hydrogen, is maintained. Preferably the radiators are laid .on their sides on the usual conveyor which carries the radiators through the furnace, and the radiators remain on their sides throughout the heating operation, thus being maintained with the same' portions of the tubes I2 in theii lower position as they are carried by the conveyor. No turning of the radiators is necessary While the radiator travels through the heating zone, the bonding material is melted and the right amount is automatically distributed to eacl transverse joint, because the bonding material melts and flows down and is pocketed at thi lowest uncovered point 2I of each projectior against the end of the projection telescopec' therein as indicated in Fig. 4. As the bonding material melts it also flows by capillaryattraction upwardly along the transverse joints, a: shown at 22 in Fig. 4, and outwardly betweerI the telescoped projections II as indicated at 20h in Fig. 4, this action continuing upwardly aI the way aroundthe circumference of the joint: until completely bonded vjoints or rings 20a are produced, as indicated inr Fig.- 5, the materia flowing out through the joint to the outside o1 the tube as indicated at 24. The portions 25 are very thin coatings of the bonding material irregularly distributed near the edges of the joint: during the capillary ilow ofthe bonding material Thus as the radiator travels through the brazying furnace, the joining material adheres to the ,also distributes by capillary attraction all the way upwardly and around .the seams I5a and I9 and forms tight joints there also.

The radiator is 'cooled sufficiently to prevenI oxidation while still inthe reducing atmosphere` After the brazing, fif desired, the radiator may be painted, galvanized, or coated with any protective material desired.

As before stated, this method may be used to make a heat exchanger of sheet metal, such as sheet steel, which has a relatively low coemcient of conductivity, and any bonding material of relatively high heat conductivity and which has suil'cient ainity for the sheet steel may be used, th'strips 20 preferably being of pure copper and taking the form of pure copper wires, a1-

though any form of strips may be used which are capable of automatically 'distributing the bonding material while melting.

Theterm radiator is used herein in a generic sense and is intended to include heat transfer devices in which the heat flows either from or to the fluid within the tubes. The word ring" is used in its broader sense, and is not intended to be limited to tubular structures of circular cross-sections.

This application is a division of my copending application Serial No. 3,490, filed. January 25, 1935, and in part a continuation of my ,copending application Serial No. 760,061, filed December 29, 1934.

My heat exchange unit has the foregoing advantages because, while it is made of a structural material, such as sheet steel of low carbon content, having a relatively low coeilicient of conductivity, .approximately such as 0.107, the structural material has a relatively highmelting point of approximately 1430 C. I-bond this structural material with a bonding material, such as copper, having a materially higher coeiiicient of conductivity, approximately such as 0.92 or several (approximately up to eight or nine) times greater than said .structural material, and having a somewhat lower melting point (approximately such as 1082 C.) than said structural material, in such a manner vthat I provide a large number of ring-like heat flow paths of relatively high heat conductivity extending unbrokenly between the interior and exterior of the tube-like structure. 'I'hese ilow paths are relatively short and hence can conduct a large amount of heat. Because of the difference in melting point of the structural and bonding materials, but both being quite high, I am able to bond the same very effectively. By the use of a hydrogen or reducing atmosphere during the bonding operation the structural and bonding materials are united together with substantially no contamination by heat conduction resistant materials. The

result is a heat exchange unit of great strength,f

and high conductivity. i

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, allcoming within the scope of the claims which follow.

What is claimed is as follows:

1. A heat exchange unit comprising a plurality of substantially parallel tube-like structures held together by a series` of substantially parallel fins integral with portions of said tube-like structures; header constructions at the ends of some of said tube-like structures controlling the flow of fluid through said tube-like structures, said` header constructions having rings telescoped with portions of said tube-like structures, and with said fins and portionsl of said tube-like structures forming a plurality of fins and a series of telescoped and aligned rings made of sheet steel as a structural material having a relatively low coeilcient of conductivity and a relatively high structural strength and high melting point, said rings being bonded together by a plurality ofseries of interposed rings of bonding material made of cuprous-steel alloy having a coeicient of conductivity several times greater than said structural material and having a lower melting point than said structural material, said rings of bonding material being of substantial thickness and extending unbrokenly from the interior to the exterior of said tube-like structures to form heat transfer paths of materially higher heat conductivity than said rings of structural material longitudinally of said tube-` like structures and to present a materially higher heat transfer bond radially between adjacent telescoped rings of sheet steel.

2. A heat exchange unit comprising a plurality of substantially parallel tube-like structures held together by a series of substantially parallel iins integral with portions of said tube-like structures, said fins and portions of said tube-like structures` forming aV plurality of ns and a series of telescope'd and aligned rings made of sheet steel as a structural material having a relatively low coeilicient of conductivity and a relatively highl structural strength and high melting point, said rings being bonded together by a plurality of series of interposed rings of bonding material made of cuprous-steel alloy having a coeillcient of conductivity several times greater than said structural material and having a lower melting pointthan said structural material, said rings of bonding material being of substantial thickness and extending unbrokenly from the interior to the exterior of said tube-like structures to form heat transfer paths of materially higher heat conductivity than said rings of structural material longitudinally of said tube-like structures and to present a materially higher heat transfer bond radially between adjacent telescoped rings of sheet steel.

JOHN KARMAZIN; 

